J. Phys. Ther. Sci. 28: 1764–1768, 2016
The Journal of Physical Therapy Science Original Article
Effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness of female patients with metabolic syndrome Seol-Jung K ang, PhD1), Eon-ho K im, PhD2), Kwang-Jun Ko, PhD3)* 1) Department
of Physical Education, Changwon National University, Republic of Korea of Sport Science, Korea Institute of Sport Science, Republic of Korea 3) Department of Sports Medicine, National Fitness Center: 424 Olympic-ro, Songpa-gu, Seoul, Republic of Korea 2) Department
Abstract. [Purpose] The purpose of this study was to investigate the effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness or female patients with metabolic syndrome. [Subjects and Methods] Subjects were randomly assigned to an exercise group (n=12) or a control group (n=11). Subjects in the exercise group performed aerobic exercise at 60–80% of maximum heart rate for 40 min 5 times a week for 12 weeks. The changes in metabolic syndrome risk factors, resting heart rate, physical fitness, and arterial stiffness were measured and analyzed before and after initiation of the exercise program to determine the effect of exercise. Arterial stiffness was assessed based on brachial-ankle pulse wave velocity (ba-PWV). [Results] Compared to the control group; The metabolic syndrome risk factors (weight, % body fat, waist circumference, systolic blood pressure, diastolic blood pressure, and HDL-Cholesterol) were significantly improved in the exercise: resting heart rate was significantly decreased; VO2max, muscle strength and muscle endurance were significantly increased; and ba-PWV was significantly decreased. [Conclusion] Aerobic exercise had beneficial effects on the resting heart rate, physical fitness, and arterial stiffness of patients with metabolic syndrome. Key words: Aerobic exercise, Metabolic syndrome, Physical fitness (This article was submitted Jan. 19, 2016, and was accepted Feb. 28, 2016)
INTRODUCTION Metabolic syndrome is a known clinical risk factor for the development of atherosclerosis and cardiovascular disease (CVD)1). Various research institutes2, 3) have suggested several diagnostic criteria for metabolic syndrome, including abdominal obesity, elevated triglycerides and decreased HDL-cholesterol associated with dyslipidemia, impaired fasting glucose or impaired glucose tolerance, and high blood pressure (BP). The simultaneous manifestation of three or more of these risk factors is associated with increased risk of the development of CVD and type 2 diabetes4, 5). In addition, a recent prospective study reported that an increase in the resting heart rate (RHR), which determines autonomic nervous system activities, actions of circulating hormones, and cardiopulmonary fitness, can result in an increase in the risk of CVD and metabolic syndrome6–8). An increase in RHR can be harmful to the heart because it can shorten the diastolic period in the cardiac cycle, increase cardiac workload due to a decreased coronary flow, and promote build up of atherosclerotic plaque9). The arterial stiffness test is used for the clinical diagnosis and assessment of atherosclerosis10). Arterial stiffness is a predictive index of CVD onset, and it is determined by the measurement of pulse wave velocity (PWV)11). PWV, which has high reliability and reproducibility, records the pulse wave from both sides of the artery as the pulse wave progresses through the interior of the *Corresponding author. Kwang-Jun Ko (E-mail:
[email protected]) ©2016 The Society of Physical Therapy Science. Published by IPEC Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (by-nc-nd) License .
Table 1. Physical characteristics of the subjects Group Exercise (n=12) Control (n=11)
Age (yrs) 48.8 ± 11.0 50.9 ± 9.2
Height (cm) 156.8 ± 7.5 157.5 ± 4.3
Weight (kg)
BMI (kg/m 2)
66.0 ± 10.0 63.1 ± 8.3
26.7 ± 2.1 25.4 ± 3.1
Values are Mean ± SD, BMI: body mass index
artery. It is calculated by dividing the distance between the two measurements points by the transit time from one point to the other12). Previous studies have reported that high arterial stiffness resulted in high PWV, and PWV was found to be increased in patients diagnosed with metabolic syndrome13, 14). In addition, a recent study by Park et al.15) suggested that there is an association between RHR and arterial stiffness. Although the reduction of risk factors is emphasized for reducing the occurrence of metabolic syndrome, reduction of RHR and arterial stiffness may be just as important. Studies have revealed that aerobic exercise is effective at improving the symptoms of metabolic syndrome16, 17). In addition, aerobic exercise reduces activation of the sympathetic nervous system, while increasing the activity of the parasympathetic nervous system resulting in reduced RHR18). A reduction in RHR may be the result of improved fitness, which is one of the primary effects of exercise19). Moreover, numerous studies of the effects of aerobic exercise on arterial stiffness have reported that aerobic exercise improves PWV in patients with obesity, type 2 diabetes, and hypertension20–22). However, very few studies have investigated the effects of aerobic exercise on arterial stiffness and RHR, which are used as predictive indices of CVD in patients with metabolic syndrome. Therefore, the present study aimed to investigate the effects of aerobic exercise on RHR, physical fitness, and arterial stiffness in female patients with metabolic syndrome.
SUBJECTS AND METHODS The subjects of in the present study were 23 females who had been diagnosed with metabolic syndrome. They were selected from among those who participated in exercise classes at a health promotion center in the “C” region of Korea. The 23 subjects were divided into an exercise (n=12) group and a control (n=11) group for the study. The study was approved by the Ethics and Research Committee involving human beings of the institution. All the subjects gave their written informed consent before participating in the study. The patients were diagnosed as having metabolic syndrome if three of the following five diagnostic criteria suggested in the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III)2) were satisfied: abdominal obesity (waist circumference≥85 cm), hypertriglyceridemia (≥150 mg/dl), low HDL-cholesterol (≤ 50 mg/dl), fasting blood glucose (≥110 mg/dl), and high BP (systolic BP≥130 mmHg or diastolic BP≥85 mmHg). The physical characteristics of the participants are described in Table 1. An automatic body-measuring instrument (Jawon Medical, Korea) was used to measure the subjects weight and height with resolutions of 0.1 kg and 0.1 cm, respectively. The weight and height measurements were used to calculate the body mass index (BMI). Waist circumference measurements were taken 0.1 cm from below the the 12th rib to the middle portion of the upper iliac crest. A body-fat analyzer (Jawon Medical, Korea) was used to measure % body fat via bioelectrical impedance analysis. BP measurements were taken after 10 min of rest with an automatic sphygmomanometer (Jawon Medical, Korea). Systolic and diastolic BP, were measured twice and the mean value was calculated. RHR was measured with wearing a wireless heart rate monitor (Polar Electro OY, Finland) for 1 min. For the blood test, blood was drawn after confirming 10 h of fasting. For blood analysis, a clinical chemistry analyzer (Hitachi 7020, Japan) was used to measure blood glucose, triglyceride, and HDL-cholesterol levels. A Helmas III (O2run, Korea) was used for the physical fitness test. As a measure of cardiopulmonary fitness, maximum oxygen uptake (VO2max) was measured on a bicycle ergometer under progressive workload. Grip strength was measured with a dynamometer by adjusting the width the maximum values (in kg) were measured twice in an upright positing. Muscle endurance was measured as the number of sit-ups performed in 30 s. Arterial stiffness was measured in a supine position using an automatic waveform analyzer (VT-1000, Colin CO, Komaki, Japan) after ≥10 min of rest. The sampling time for the 1st pulse wave recording was set to 10 s and two consecutive recordings were obtained for each participant. The mean of the automatically calculated values was used in the analysis. The 12-week aerobic exercise program consisted of warm-up exercise, main exercise, and cool-down exercise, in that order, and a total of 5 sessions were performed per week. Warm-up exercise consisted of 5 min of walking followed by 10 min of stretching, and the cool-down exercise consisted of 10 min of stretching. Aerobic exercise, which was the main exercise, consisted of 40 min of walking on a treadmill at 60–80% of maximum HR. During the aerobic exercise, the participants wore a Polar Heart Rate Analyzer (Polar Electro OY, Finland) to monitor exercise intensity and keep it within the target heart rate range. Data analysis in the present study was performed via two-way ANOVA with repeated measures using SAS (version 9.1), and a significance level (a) of 0.05.
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Table 2. Changes in metabolic syndrome risk factors Variability Weight (kg) % fat Waist circumference (cm) Triglyceride (mg/dl) HDL-Cholesterol (mg/dl) Fasting blood glucose (mg/dl) Systolic blood pressure (mmHg) Diastolic blood pressure (mmHg)
Group Exercise Control Exercise Control Exercise Control Exercise Control Exercise Control Exercise Control Exercise Control Exercise Control
Table 3. Changes in resting heart rate and physical fitness levels
Pre-test
Post-test
66.0 ± 10.0 63.1 ± 8.3 37.0 ± 3.5 33.9 ± 3.4 87.1 ± 5.7 86.0 ± 7.7 166.8 ± 72.0 171.1 ± 61.1 38.3 ± 5.6 36.9 ± 9.6 110.6 ± 13.6 109.3 ± 13.0 131.3 ± 9.9 132.6 ± 8.8 81.6 ± 4.9 80.5 ± 2.8
63.1 ± 8.9** 62.3 ± 8.3 34.9 ± 3.4* 33.0 ± 3.2 85.1 ± 5.2** 85.0 ± 7.2 151.0 ± 67.5 162.8 ± 63.7 44.8 ± 5.3** 37.7 ± 9.1 103.2 ± 13.9*** 108.1 ± 12.6 125.8 ± 14.4** 130.3 ± 9.8 78.9 ± 6.8** 79.7 ± 2.7
Values are Mean ± SD, *significant difference, p
